Method of forming sinkers for knitting machines



Aug. 22, 1933. L. B. HOLT 1,923,827

METHOD OF FORMING SINKERS FOR KNITTING MACHINES Fild Oct. 24. 1932 INVENTOR LAURENCE B. HOLT BY HIS ATTORNEYS MMM Patented Aug. 22, 1933 UNITED STATES PATENT; OFFICIE METHOD OF FORMING SINKERS FOR KNITTING MACHINES Application October 24, 1932. Serial No. 639,348

5 Claims.

This invention relates to a method of manufacturing sinkers for knitting machines and it is an object of this invention to provide a method of forming sinkers which will produce sinkers properly formed and tempered and which will not necessitate the straightening of the sinkers after tempering. It is also an object of this invention to provide a method of forming sinkers from continuous metal strips.

In the drawing- Fig. 1 is a plan view of the metal strip used;

Fig. 2 is a plan view of the strip of Fig. 1 after the first operation of reducing its thickness at intervals and punching index openings therein;

Fig. 3 is an edge view of the strip shown in Fig. 2;

Fig. 4 is a plan view of strip of Fig. 2 after the sinkers have been punched therefrom; and

Figs. 5 and 6 are plan and edge views, respectively, of a sinker punched from the strip of Fi 4.

In the manufacture of sinkers in accordance with this invention, the sinkers are formed from a strip 1 of steel of suitable composition which, for convenience in handling, is rolled into coils of suitable length and weight. The strip is first annealed so as to make it of substantially uniform softness throughout. The annealed strip is then passed through one or more sets of rolls which reduce the thickness of the strip at uniform intervals providing areas 2 of reduced thickness and forming a strip having areas 3 of normal thickness alternating with the areas 2 of reduced thickness. During the same passages through the rolls the index openings 4 are punched in the strip to serve as means for correctly positioning the portions of reduced and normal thickness for a sub-.

sequent operation.

The strip is then subjected to a hardening and tempering treatment, the furnace and cooling apparatus used being of types permitting of the continuous passage of the strip therethrough, and the strip, during this operation, is kept under sufficient tension to hold the strip flap and prevent warping or distortion thereof. After tempering, the strip may be polished and the sinkers are then punched from the tempered strip, the index openings 4 serving to accurately position the portions of the strip of reduced and normal thickness with respect to the dies which punch the sinkers therefrom. The sinkers 6 shown in Figs. 5 and 6 which illustrate but one design of sinker to which this invention is applicable have the yarn engaging portion formed from a portion of the strip of reduced thickness while the remainder of the sinker is formed from a portion of the strip of normal thickness.

Upon punching, the sinkers are completed except for rumbling and inspection. Sinkers made as above described being punched from a hardened fiat strip are free from distortion and the slow and costly straightening operation necessary to correct distortion when sinkers are tempered after punching is unnecessary, and loss due to rejections because of distortion is avoided. Further, tempering the sinkers in the strip permits of maintaining the temper of the sinkers more uniform than when the sinkers are tempered after being punched from the strip.

I claim- 1. In the manufacture of sinkers for knitting machines the steps of reducing the thickness of an annealed strip at regular intervals and punching an index hole adjacent each reduced portion, tempering the strip while holding the strip under tension and punching sinkers from sections of the strip comprising a portion of reduced thickness and an adjacent portion of regular thickness.

2. In the manufacture of sinkers for knitting machines, thesteps of reducing at intervals the thickness of an annealed metal strip, tempering the strip and punching the sinkers from sections of the strip comprising portions of reduced and normal thicknesses.

3. In the manufacture of sinkers for knitting machines, the steps of reducing at regular intervals the thickness of an annealed metal strip of uniform thickness, tempering the strip while held under tension and punching the sinkers from sections of the tempered strip comprising portions of reduced and normal thicknesses.

4. In the manufacture of sinkers for knitting machines, the steps of rolling an annealed strip to reduce its thickness at regular intervals, tempering the strip while under tension and punching the sinkers from sections of the hardened strip comprising portions of reduced and normal thicknesses.

5. In the manufacture of sinkers for knitting machines, the steps of rolling an annealed strip to reduce its thickness at regular intervals, tempering the strip in a continuous process while under tension and punching the sinkers from sections comprising portions of normal and reduced thicknesses.

LAURENCE B. HOLT. 

